THE JOINTS 155
marked. The insertions of the supra-spinatus, infm-spinatus and pectoralis minor are blended with the capsule. The cotyloid ligament and tendon of the biceps are as in Man. The range of movement of the shoulder joint is considerable.
The sterno-clavicular joint is much as in Man, and its meniscus may be ossified. The acromio-clavicular joint has a partial meniscus. The costo-coracoid membrane is strong, but it is not always possible to separate the coraco-clavicular ligament into conoid and trapezoid parts.
Elbow-joint.—Keith (,96) does not draw attention to any essential difterence between this joint in the Apes and that in Man; and Fick (247) points out that the ligaments are similar in the Orang and in Man. In the Chimpanzee the posterior part of the capsule has a strong band running from the tip of the olecranon to the outer part of the olecranon fossa; the anterior part of the capsule is strong by reason of the interlacing fibres which compose it. The internal lateral ligament is very powerful, and is stronger than the external lateral ligament.
Superior Radio-ulnar Joint—The only point of difference between this joint in the Chimpanzee and that in Man is the absence of the oblique cord, Keith (96) points out that it is strong in the Quadrumana examined by him.
Wrist-joint,—In the Chimpanzee both aspects of the carpus are covered by ligaments, but there is no centre of radiation. The following bands deserve mention :—
(1) A strong band from the base of the radial styloid process to the trapezium and os magnum. A weak external lateral ligament.